The editorial in the September 1982 issue of this journal and many articles before and since have addressed the problem of informed consent. Is it possible? Is it a useful concept? Is there anything new to be said about it? In this article the basic rationale of the rule (patient autonomy) is explained and the extent of the rule explored. Various exceptions have been offered by the law and an attempt is made to catalogue the chief of these. A number of specially vulnerable groups are then identified, the most important, and vexed, being children. How can informed consent be secured in the case of young patients? Finally, a few problems are mentioned in an attempt to get this subject back to reality. The appeal to the principle primum non nocere may be medical paternalism in disguise. Informed consent is the competing principle that reminds us of the primacy of human autonomy. A pointer is given to the future: even the use of sound recordings to explain medical procedures and to activate informed consent so that it may become a reality and not just a lawyer's myth, should be considered.